JP6734796B2 - Marine diesel engine and engine control device and method - Google Patents

Description

The present invention relates to a marine diesel engine equipped with a selective catalytic reduction (SCR) denitration device.

A marine diesel engine, which is a main engine mounted on a ship, contains nitrogen oxides (NOx) in exhaust gas, and therefore is equipped with a device for reducing this NOx. As a device for reducing this NOx, there is an SCR denitration device. This SCR denitration device removes nitrogen oxides in exhaust gas by supplying a reducing agent having a function of reducing nitrogen oxides into the exhaust pipe to promote the reaction between the nitrogen oxides in the exhaust gas and the reducing agent. , Is to be reduced. However, in order for this SCR denitration device to efficiently remove the nitrogen oxides in the exhaust gas by the catalyst, it is necessary to maintain the exhaust gas temperature at or above the predetermined reaction temperature.

Japanese Patent No. 5781290 Utility Model Registration No. 317346

In Patent Document 1 described above, the temperature of the exhaust gas is set to a predetermined value by raising the temperature of the exhaust gas using a burner or spraying an aqueous solution containing a reducing agent on the high temperature exhaust gas immediately after being discharged from the exhaust port of the engine. The reaction temperature is maintained above. Therefore, the cost may increase.

Further, the number of revolutions of the marine diesel engine increases when the operation is started. At this time, since the engine is a rotating machine and causes resonance and the like, there is a dangerous speed range (Barred Range, Critical Speed) in which long-time operation in a predetermined speed range is prohibited. This is described in Patent Document 1 mentioned above. Therefore, when the engine speed reaches the dangerous speed range, the ship is required to quickly exit the dangerous speed range by increasing the speed in a short time.

The present invention solves the above-mentioned problems, and an object of the present invention is to provide a marine diesel engine, an engine control device and a method for achieving both denitration of exhaust gas and stable engine driving.

The marine diesel engine of the present invention for achieving the above object is an engine body, a denitration device provided in the exhaust line of the exhaust gas discharged from the engine body, and an exhaust gas that raises the temperature of the exhaust gas flowing into the denitration device. A temperature raising device; and a control device that controls the operation of the exhaust gas temperature raising device and stops the operation of the exhaust gas temperature raising device when the engine speed is in a preset dangerous speed range. It is a feature.

Therefore, when the control device operates the exhaust gas temperature raising device, the temperature of the exhaust gas from the engine rises, and the denitration device carries out the denitration treatment of the exhaust gas. Then, the control device stops the operation of the exhaust gas temperature raising device when the engine speed enters the dangerous speed range. Here, even if the operation of the exhaust gas temperature raising device is stopped, the temperature of the exhaust gas does not drop sharply because the heat capacity of the denitration device is large, and the denitration device can appropriately perform the denitration treatment of the exhaust gas. it can. Further, when the operation of the exhaust gas temperature raising device is stopped, the combustion state of the engine body is stabilized, so that the control device can appropriately increase the engine rotation speed and quickly exit the dangerous rotation speed range. As a result, it is possible to achieve both denitration of exhaust gas and stable engine driving.

In the marine diesel engine of the present invention, the control device stops the operation of the exhaust gas temperature raising device when the command value is input when the command value for increasing the engine speed exceeds the dangerous speed range. It is characterized by doing.

Therefore, since the command value is input and the operation of the exhaust gas temperature raising device is stopped, the operation of the exhaust gas temperature raising device can be stopped before the engine speed reaches the dangerous rotational speed range. It is possible to stabilize the combustion state and appropriately increase the engine speed to quickly exit the dangerous speed range.

In the marine diesel engine of the present invention, the control device stops the operation of the exhaust gas temperature raising device when the current engine speed reaches the dangerous speed range.

Therefore, since the operation of the exhaust gas temperature raising device is stopped when the engine speed reaches the dangerous speed range, the operation of the exhaust gas temperature raising device is reliably performed when the engine speed reaches the dangerous speed range. The engine can be stopped, the combustion state of the engine body can be stabilized, the engine speed can be appropriately increased, and the critical speed range can be quickly exited.

In the marine diesel engine of the present invention, a margin lower limit value of the dangerous speed range lower than the lower limit value of the dangerous speed range obtained by adding a preset margin value to the lower limit value of the dangerous speed range is set, and The control device is characterized in that the operation of the exhaust gas temperature raising device is stopped when the current engine speed reaches the margin lower limit value.

Therefore, since the operation of the exhaust gas temperature raising device is stopped when the engine speed reaches the margin lower limit value, it is necessary to stop the operation of the exhaust gas temperature raising device before the engine speed reaches the dangerous speed range. Therefore, the combustion state of the engine body can be made stable, and the engine speed can be appropriately increased to quickly get out of the dangerous speed range.

The marine diesel engine of the present invention is characterized in that the control device starts the operation of the exhaust gas temperature raising device when the current engine speed has passed the dangerous speed range.

Therefore, when the engine speed goes out of the dangerous speed range, the operation of the exhaust gas temperature raising device starts.Therefore, the denitration device should properly perform the denitration treatment of the exhaust gas with the exhaust gas temperature raising device stopped for the shortest period. You can

In the marine diesel engine of the present invention, the control device starts the operation of the exhaust gas temperature raising device after a lapse of a predetermined time set in advance after the current engine speed has passed through the dangerous speed range. I am trying.

Therefore, since the exhaust gas temperature raising device starts to operate after a predetermined time has elapsed after the engine speed has passed through the dangerous rotation speed range, the exhaust gas temperature raising device can be operated after the engine speed has completely passed through the dangerous rotation speed range. As a result, the engine body can be ensured to be safe, and the exhaust gas can be properly denitrated by the denitration device.

Further, the engine control device of the present invention includes an engine body, a denitration device provided in an exhaust line of exhaust gas discharged from the engine body, and an exhaust gas temperature raising device that raises the temperature of exhaust gas flowing into the denitration device. In a marine diesel engine provided, the operation of the exhaust gas temperature raising device is controlled, and the operation of the exhaust gas temperature raising device is stopped when the engine speed is in a preset dangerous rotational speed range. Is.

Therefore, when the exhaust gas temperature raising device is operated, the temperature of the exhaust gas from the engine rises, and the denitration device carries out the denitration treatment of the exhaust gas. Then, when the engine speed enters the dangerous speed range, the operation of the exhaust gas temperature raising device is stopped. Here, even if the operation of the exhaust gas temperature raising device is stopped, the temperature of the exhaust gas does not drop sharply because the heat capacity of the denitration device is large, and the denitration device can appropriately perform the denitration treatment of the exhaust gas. .. Further, when the operation of the exhaust gas temperature raising device is stopped, the combustion state of the engine body is stabilized, so that the engine speed can be appropriately increased and the dangerous speed range can be quickly exited. As a result, it is possible to achieve both denitration of exhaust gas and stable engine driving.

Further, the engine control method of the present invention includes a step of increasing the temperature of the exhaust gas from the engine and a denitration process of the exhaust gas when the ship is at least in the air pollutant emission control sea area, and an engine speed. Stopping the process of raising the temperature of the exhaust gas when enters into a preset dangerous rotational speed range.

Therefore, if the operation of the exhaust gas temperature raising device is stopped when the engine speed enters the dangerous speed range, the combustion state of the engine is stabilized, so the engine speed is appropriately increased and the dangerous speed is quickly increased. You can get out of the area. As a result, it is possible to achieve both denitration of exhaust gas and stable engine driving.

According to the marine diesel engine and the engine control device and method of the present invention, it is possible to achieve both denitration of exhaust gas and stable driving of the engine.

FIG. 1 is a schematic configuration diagram showing the marine diesel engine of the first embodiment. FIG. 2 is a time chart showing the operation of the SCR denitration device. FIG. 3 is a time chart showing the operation of the SCR denitration device in the marine diesel engine of the second embodiment. FIG. 4 is a time chart showing the operation of the SCR denitration device in the marine diesel engine of the third embodiment. FIG. 5 is a time chart showing the operation of the SCR denitration device in the marine diesel engine of the fourth embodiment.

Hereinafter, preferred embodiments of a marine diesel engine, an engine control device and a method according to the present invention will be described in detail with reference to the accompanying drawings. It should be noted that the present invention is not limited to this embodiment, and when there are a plurality of embodiments, the present invention also includes those configured by combining the embodiments.

[First Embodiment]
FIG. 1 is a schematic configuration diagram showing the marine diesel engine of the first embodiment.

In the first embodiment, as shown in FIG. 1, a marine diesel engine 10 includes an engine body 11, a supercharger 12, an SCR denitration device 13, an exhaust gas temperature raising device 14, and a control device 15. ing.

The engine body 11 is a propelling engine (main engine) that drives and rotates a propeller for propelling via a propeller shaft. The engine body 11 is a uniflow scavenging exhaust type diesel engine, which is a two-stroke diesel engine, in which the flow of intake and exhaust in the cylinder is made one direction from the lower side to the upper side to eliminate the residual exhaust. Is. The engine body 11 includes a plurality of cylinders (combustion chambers) 21 in which pistons move up and down, a scavenging trunk 22 that communicates with each cylinder 21, and an exhaust manifold (exhaust static pressure pipe) 23 that communicates with each cylinder 21. .. A scavenging port 24 is provided between each cylinder 21 and the scavenging trunk 22, and an exhaust port 25 is provided between each cylinder 21 and the exhaust manifold 23. In the engine body 11, the scavenging trunk 22 is connected to the air supply line G1 and the exhaust manifold 23 is connected to the exhaust line G2.

The marine diesel engine 10 includes a supercharger 12. The supercharger 12 is configured by connecting a compressor 31 and a turbine 32 by a rotating shaft 33 so as to rotate integrally. The intake port G3 is connected to the intake side of the compressor 31, and the air supply line G1 is connected to the discharge side. The turbine 32 has an exhaust line G2 connected to the inflow side and an exhaust line G4 connected to the exhaust side. Therefore, the turbine 32 is rotated by the exhaust gas discharged from the exhaust manifold 23 to the exhaust line G2, the rotation of the turbine 32 is transmitted by the rotating shaft 33, and the compressor 31 is rotated. The compressor 31 compresses the air taken in through the intake port G3 and supplies the compressed air to the scavenging trunk 22 through the air supply line G1.

The SCR denitration device 13 is provided in the exhaust line G4. The SCR denitration device 13 includes an SCR reactor and a reducing agent supply device 42. The SCR denitration device 13 supplies a reducing agent having a function of reducing nitrogen oxides (NOx) to the exhaust line G4, and promotes the reaction of NOx and the reducing agent with the exhaust gas supplied with the reducing agent, thereby reducing the exhaust gas. It removes and reduces NOx in the inside. Therefore, the reducing agent supply device 42 is provided upstream of the SCR reactor in the exhaust line G4 in the exhaust gas flow direction. The reducing agent supply device 42 can diffuse the reducing agent in the exhaust line G4 in which the exhaust gas flows by supplying the reducing agent toward the downstream side of the entire surface of the exhaust line G4. As the reducing agent, for example, ammonia water, gaseous ammonia, urea water or the like can be used.

The turbine 32 of the supercharger 12 described above is connected to the downstream side of the exhaust line G2 from the engine body 11 on the inflow side, and on the exhaust side is an exhaust line G4 for discharging the exhaust gas that has rotated the turbine 32, that is, the SCR denitration device 13 Are connected. The exhaust line G4 is connected to a chimney (funnel) not shown.

The SCR denitration device 13 needs to maintain the exhaust gas temperature at or above a predetermined reaction temperature in order to efficiently remove NOx in the exhaust gas with a catalyst. The exhaust gas temperature raising device 14 extracts a part of the exhaust gas flowing into the turbine 32 of the supercharger 12. The exhaust gas temperature raising device 14 is composed of an extraction gas line G5 and an extraction gas valve 51. The extraction gas line G5 has a proximal end connected to the upstream side of the turbine 32 in the exhaust line G2, and a distal end connected to the downstream side of the turbine 32 in the exhaust line G4 and upstream of the SCR denitration device 13. The extraction gas valve 51 is provided in the extraction gas line G5.

Therefore, when the extraction gas valve 51 is opened, the amount of exhaust gas flowing into the turbine 32 from the exhaust line G2 decreases, and the turbine speed decreases. When the turbine rotation speed decreases, the rotation speed of the compressor 31 integrally connected to the turbine 32 via the rotation shaft 33 decreases, and the supercharging pressure decreases, so that each cylinder 21 of the engine main body 11 from the air supply line G1. The amount of air supplied to the is reduced. Then, the air-fuel ratio of the engine body 11 becomes small, the combustion temperature rises, and the temperature of the exhaust gas also rises.

The exhaust gas temperature raising device 14 is not limited to the one including the extraction gas line G5 and the extraction gas valve 51. For example, the exhaust gas temperature raising device 14A extracts a part of the air supplied from the compressor 31 of the supercharger 12 to the engine body 11. The exhaust gas temperature raising device 14A includes an extraction line G6 and an extraction valve 52. The extraction line G6 has a base end connected to the air supply line G1 and a front end open to the atmosphere. The extraction valve 52 is provided in the extraction line G6. Therefore, when the bleed valve 52 is opened, the amount of air supplied from the compressor 31 to each cylinder 21 of the engine body 11 through the air supply line G1 decreases. Then, the air-fuel ratio of the engine body 11 becomes small, the combustion temperature rises, and the temperature of the exhaust gas also rises.

Further, other exhaust gas temperature raising devices include, for example, a control device that controls the opening/closing timing of an exhaust valve (not shown) provided in the engine body 11, and a fuel injection valve (not shown) provided in the engine body 11. A control device for controlling the injection amount or controlling the injection timing may be applied.

The air supply line G1 is provided with an air cooler (cooler) 61. The air cooler 61 cools air by exchanging heat between the air compressed by the compressor 31 and having a high temperature and the cooling water.

By operating the steering handle 71, the ship can switch between forward and backward travel, stop, and navigation speed. From the forward side, navigation full ahead (Navigation Full Ahead: full forward speed at voyage (usual) speed) as a navigation mode, full ahead (full ahead: full forward speed at port speed) as a harbor navigation mode, Half Ahead: Half forward speed at harbor speed, Slow Ahead: Slow forward speed at harbor speed, Dead Slow Ahead: Forward speed at harbor speed There is a main engine stop at the slowest speed). From the main engine stop to the reverse side, dead slow astern (Dead Slow Astern: slow reverse speed at the port speed), slow astern (slow reverse speed at the port speed), half astern (Half Astern: reverse half speed at port speed) and Full Astern (full reverse speed). By switching the steering handle 71 to each position, the occupant can switch forward, backward, stop, and navigation speed of the ship.

The control device 15 is connected to the control handle 71, and controls the engine body 11 based on a signal (request load) from the control handle 71. For example, the control device 15 adjusts the fuel injection amount, the fuel injection timing, the exhaust valve opening/closing timing, and the like in the engine body 11 based on the signal from the steering handle 71, and adjusts the engine speed to a predetermined speed. , The navigation speed of the ship can be adjusted.

Further, when a ship travels, the NOx-SOA and PM in the exhaust gas are set to a stricter air pollutant emission control area (NOx-ECA) than the general sea area. The control device 15 operates the SCR denitration device 13 and the exhaust gas temperature raising device 14 if the current operating area of the ship is this ECA that regulates the emission amount of NOx. In this case, an occupant may input a signal for operating the SCR denitration device 13 and the exhaust gas temperature raising device 14 to the control device 15 by an operation switch (not shown), or the control device 15 automatically operates based on the current navigation position. Alternatively, the SCR denitration device 13 and the exhaust gas temperature raising device 14 may be operated. The same applies to the stoppage of the operation of the SCR denitration device 13 and the exhaust gas temperature raising device 14.

That is, the control device 15 stops the operation of the SCR denitration device 13 and the exhaust gas temperature raising device 14 if the current operating area of the ship is outside the NOx-ECA (NOx restricted area). That is, the supply of the reducing agent to the exhaust line G4 by the reducing agent supply device 42 is stopped, and the extraction gas valve 51 is closed to shut off the extraction gas line G5. Alternatively, the bleed valve 52 is closed to shut off the bleed line G6. On the other hand, the control device 15 operates the SCR denitration device 13 and the exhaust gas temperature raising device 14 if the current operating area of the ship is within the NOx-ECA (NOx regulated area). That is, the supply of the reducing agent to the exhaust line G4 by the reducing agent supply device 42 is started, and the extraction gas valve 51 is opened to allow the extraction gas line G5 to flow. Alternatively, the extraction valve 52 is opened to allow the extraction line G6 to flow.

Thus, when the current operating area of the ship is within NOx-ECA, the NOx in the exhaust gas is removed and reduced by operating the SCR denitration device 13 and the exhaust gas temperature raising device 14, but at this time, The combustion state of the engine body 11 is slightly deteriorated because the exhaust gas temperature rises. On the other hand, the marine diesel engine 10 has a critical rotation speed range in which long-time operation in a predetermined rotation speed range is prohibited because resonance or the like occurs in the engine body 11 when the rotation speed increases. In the present embodiment, the control device 15 controls the engine speed to reach the critical speed range when the ship is in the NOx-ECA and the SCR denitration device 13 and the exhaust gas temperature raising devices 14 and 14A are operating. Then, the operation of the exhaust gas temperature raising devices 14, 14A is stopped.

Specifically, when a command value for increasing the engine speed beyond the dangerous speed range is input from the steering wheel 71 by operating the steering wheel 71, the control device 15 inputs the exhaust gas temperature when the command value is input. The operation of the raising devices 14 and 14A is stopped. Then, the control device 15 starts the operation of the exhaust gas temperature raising devices 14 and 14A when the current engine speed passes through the dangerous speed range.

Therefore, the engine body 11 is provided with a rotation speed sensor 72 that detects the engine rotation speed. The rotation speed sensor 72 is connected to the control device 15 and outputs the detected engine rotation speed to the control device 15.

Hereinafter, the operation of the marine diesel engine 10 of the first embodiment will be described.

As shown in FIG. 1, in the engine body 11, when the combustion gas is supplied from the scavenging trunk 22 into the cylinder 21, the combustion gas is compressed by a piston (not shown), and the combustion gas becomes high in temperature. On the other hand, when fuel is injected, it spontaneously ignites and burns. Then, the generated combustion gas is discharged from the exhaust manifold 23 to the exhaust line G2 as exhaust gas. The exhaust gas discharged from the engine body 11 is discharged to the exhaust line G4 after rotating the turbine 32 in the supercharger 12, and is discharged to the outside from the exhaust line G4.

When the turbine 32 is rotated by the exhaust gas, the supercharger 12 is rotated by the rotation of the turbine 32 being transmitted to the compressor 31 by the rotating shaft 33. The compressor 31 compresses the air taken in through the intake port G3 and supplies the compressed air to the scavenging trunk 22 through the air supply line G1. At this time, the air supplied from the air supply line G1 to the scavenging trunk 22 is cooled by the air cooler 61.

Further, the control device 15 stops the operation of the SCR denitration device 13 and the exhaust gas temperature raising device 14 if the current operating area of the ship is outside the ECA. On the other hand, the control device 15 operates the SCR denitration device 13 and the exhaust gas temperature raising device 14 if the current operating area of the ship is within NOx-ECA. First, when the exhaust gas temperature raising device 14 operates, the extraction gas valve 51 is opened, the amount of exhaust gas flowing into the turbine 32 from the exhaust line G2 is reduced, and the amount of air supplied from the air supply line G1 to the engine body 11 is reduced. By doing so, the temperature of the exhaust gas rises. Alternatively, when the exhaust gas temperature raising device 14A operates, the bleed valve 52 is opened and the amount of air supplied from the air supply line G1 to the engine body 11 decreases, so that the temperature of the exhaust gas also rises. Next, when the SCR denitration device 13 operates, the reducing agent supply device 42 supplies the reducing agent to the exhaust line G4. Then, the SCR reactor in the exhaust line G4 promotes the reaction between the reducing agent from the reducing agent supply device 42 and the exhaust gas heated to a predetermined reaction temperature or higher, thereby removing and reducing NOx in the exhaust gas. ..

Furthermore, when the ship is in the ECA and the SCR denitration device 13 and the exhaust gas temperature raising device 14 are operating, the control device 15 controls the exhaust gas temperature raising device 14 when the engine speed reaches the dangerous speed range. Stop operation.

Here, the control of the SCR denitration device 13 and the exhaust gas temperature raising device 14 will be described. FIG. 2 is a time chart showing the operation of the SCR denitration device.

The engine control method according to the first embodiment performs a process of increasing the temperature of exhaust gas from the engine body 11 and a denitration process of exhaust gas when the ship is at least in the air pollutant emission control sea area; And a step of stopping the process of increasing the temperature of the exhaust gas when the rotation speed enters a preset dangerous rotation speed range.

As shown in FIGS. 1 and 2, when the operating area of the ship is within the ECA (regulated area) (ON), the SCR denitration device 13 is activated (ON) and the exhaust gas temperature raising device 14 is activated to perform extraction. The gas valve 51 is opened, and the exhaust gas is subjected to denitration processing. Then, at time t1, the steering wheel 71 is operated and a command value for increasing the engine speed beyond the dangerous speed range is output. That is, when the current engine speed Ne1 is equal to or lower than the lower limit value NeL of the dangerous speed range A, the command value for increasing from this engine speed Ne1 to the engine speed Ne2 higher than the upper limit NeU of the dangerous speed range A is Is output.

When this command value is input at time t1, the control device 15 stops the operation of the exhaust gas temperature raising device 14 and closes the extraction gas valve 51. Further, the control device 15 increases the engine speed by performing control such as increasing the amount of fuel input based on this command value. Then, at time t2, the engine speed reaches the lower limit value NeL and enters the dangerous speed range A, but at this time, since the operation of the exhaust gas temperature raising device 14 is stopped, the combustion of the engine body 11 is stopped. The state is stable, the engine speed rapidly rises, and exits the dangerous speed range A at time t3. Further, during the period T1 in which the engine speed is in the dangerous speed range A, the exhaust gas temperature rising process is stopped, but the exhaust gas temperature does not drop early and the exhaust gas denitration process continues. Will be implemented.

Then, at this time t3, when the engine speed exceeds the upper limit value NeU of the dangerous speed range A, the control device 15 starts the operation of the exhaust gas temperature raising device 14 and opens the extraction gas valve 51. Then, the exhaust gas temperature increasing device 14 starts the exhaust gas temperature increasing process again, and the exhaust gas denitration process is continuously performed. After that, at time t4, the engine speed reaches the target engine speed Ne2. Then, at time t5, when the operating area of the ship is outside the ECA (regulated area) (OFF), the operation of the SCR denitration device 13 is stopped (OFF) and the operation of the exhaust gas temperature raising device 14 is stopped. The extraction gas valve 51 is closed, and the exhaust gas denitration process ends.

As described above, in the marine diesel engine of the first embodiment, the engine body 11, the SCR denitration device 13 provided in the exhaust line G4 of the exhaust gas discharged from the engine body 11, and the exhaust gas flowing into the SCR denitration device 13 And an exhaust gas temperature raising device 14 for raising the temperature of the exhaust gas, and a control device for controlling the operation of the exhaust gas temperature raising device 14 and for stopping the operation of the exhaust gas temperature raising device 14 when the engine speed is in a preset dangerous rotational speed range. 15 and.

Accordingly, when the engine speed enters the dangerous speed range A, the combustion state of the engine body 11 is stabilized by stopping the operation of the exhaust gas temperature raising device 14, so that the engine speed can be appropriately increased and It is possible to get out of the dangerous speed range. At this time, even if the operation of the exhaust gas temperature raising device 14 is stopped, the temperature of the exhaust gas does not drop sharply because the heat capacity of the SCR denitration device 13 is large, and the SCR denitration device 13 properly performs the denitration treatment of the exhaust gas. Can be carried out. As a result, it is possible to achieve both denitration of exhaust gas and stable engine driving.

In the marine diesel engine of the first embodiment, when a command value for increasing the engine speed beyond the dangerous speed range A is input, the control device 15 operates the exhaust gas temperature increasing device 14 when the command value is input. To stop. Therefore, since the operation of the exhaust gas temperature raising device 14 is stopped when the command value is input, the operation of the exhaust gas temperature raising device 14 can be stopped before the engine speed reaches the dangerous rotational speed range A. The combustion state of the main body 11 can be stabilized and the engine speed can be appropriately increased to quickly exit the dangerous speed range A.

In the marine diesel engine of the first embodiment, the control device 15 starts the operation of the exhaust gas temperature raising device 14 when the current engine speed passes through the dangerous speed range A. Therefore, the SCR denitration device 13 can appropriately perform the denitration treatment of the exhaust gas with the exhaust gas temperature raising device 14 stopped for the shortest period.

Further, in the engine control device of the first embodiment, the operation of the exhaust gas temperature raising device 14 is controlled so as to be stopped when the engine speed is in the preset dangerous speed range A. Therefore, when the engine speed enters the dangerous speed range A, the combustion state of the engine body 11 can be stabilized and the critical speed range can be quickly exited.

Further, in the engine control method of the first embodiment, a process of increasing the temperature of the exhaust gas from the engine body 11 when the ship is in the ECA and a process of performing denitration of the exhaust gas, And a step of stopping the process of raising the temperature of the exhaust gas when the rotation speed enters a preset dangerous rotation speed range A. Therefore, it is possible to achieve both denitration of exhaust gas and stable driving of the engine.

[Second Embodiment]
FIG. 3 is a time chart showing the operation of the SCR denitration device in the marine diesel engine of the second embodiment. The basic configuration of the marine diesel engine of the present embodiment is almost the same as that of the above-described first embodiment, and will be described with reference to FIG. 1 and has the same functions as those of the above-described first embodiment. The members having the same reference numerals are given and detailed description thereof is omitted.

In the marine diesel engine of the second embodiment, as shown in FIG. 1, the control device 15 operates the exhaust gas temperature raising device 14 (14A) when the current engine speed reaches the dangerous speed range A. I'm trying to stop.

As shown in FIG. 1 and FIG. 3, when the operating area of the ship is within the ECA (regulated area) (ON), the SCR denitration device 13 is activated (ON) and the exhaust gas temperature raising device 14 is activated. The gas valve 51 is opened, and the exhaust gas is subjected to denitration processing. Then, at time t11, the steering wheel 71 is operated, and a command value for increasing the engine speed beyond the dangerous speed range A is output. When this command value is input at time t11, the control device 15 increases the engine speed by performing control such as increasing the amount of fuel input based on this command value.

At time t12, the control device 15 stops the operation of the exhaust gas temperature raising device 14 and closes the extraction gas valve 51 at the same time when the engine speed reaches the lower limit value of the dangerous speed range A. Although the engine speed of the engine body 11 is in the dangerous speed range A, the combustion state is stable because the operation of the exhaust gas temperature raising device 14 is stopped at this time, and the engine speed is rapidly increased. Ascends and exits the dangerous rotation speed range A at time t13. Further, during the period T1 in which the engine speed is in the dangerous speed range A, the exhaust gas temperature rising process is stopped, but the exhaust gas temperature does not drop early and the exhaust gas denitration process continues. Will be implemented.

Then, at this time t13, when the engine speed passes through the dangerous speed range A, the control device 15 starts the operation of the exhaust gas temperature raising device 14 and opens the extraction gas valve 51. Then, the exhaust gas temperature increasing device 14 starts the exhaust gas temperature increasing process again, and the exhaust gas denitration process is continuously performed. After that, at time t14, the engine speed reaches the target engine speed. Then, at time t15, when the operating area of the ship is outside the ECA (regulated area) (OFF), the operation of the SCR denitration device 13 is stopped (OFF) and the operation of the exhaust gas temperature raising device 14 is stopped. The extraction gas valve 51 is closed, and the exhaust gas denitration process ends.

As described above, in the marine diesel engine of the second embodiment, the control device 15 stops the operation of the exhaust gas temperature raising device 14 when the current engine speed reaches the dangerous speed range A. Therefore, when the engine speed reaches the dangerous engine speed range A, the operation of the exhaust gas temperature raising device 14 can be surely stopped, the combustion state of the engine body 11 is stabilized, and the engine speed is appropriately adjusted. It is possible to increase and get out of the dangerous speed range quickly.

[Third Embodiment]
FIG. 4 is a time chart showing the operation of the SCR denitration device in the marine diesel engine of the third embodiment. The basic configuration of the marine diesel engine of the present embodiment is almost the same as that of the above-described first embodiment, and will be described with reference to FIG. 1 and has the same functions as those of the above-described first embodiment. The members having the same reference numerals are given and detailed description thereof is omitted.

In the marine diesel engine of the third embodiment, as shown in FIG. 1, the control device 15 adds the preset margin value B to the lower limit value of the dangerous rotation speed range A and sets the lower limit value of the dangerous rotation speed range A. A lower margin lower limit value of a lower dangerous speed region is set, and when the current engine speed reaches the lower margin limit value, the operation of the exhaust gas temperature raising device 14 (14A) is stopped.

As shown in FIGS. 1 and 4, when the operating area of the ship is within the ECA (regulated area) (ON), the SCR denitration device 13 operates (ON) and the exhaust gas temperature raising device 14 operates to extract the water. The gas valve 51 is opened, and the exhaust gas is subjected to denitration processing. Then, at time t21, the steering wheel 71 is operated, and a command value for increasing the engine speed beyond the dangerous speed range A is output. When the command value is input at time t21, the control device 15 increases the engine speed by performing control such as increasing the amount of fuel input based on the command value.

At time t22, when the engine speed reaches the margin lower limit value of the dangerous speed range A, the control device 15 stops the operation of the exhaust gas temperature raising device 14 and closes the extraction gas valve 51. Then, at time t23 when the predetermined time T2 has elapsed, the engine speed reaches the dangerous speed range A. It is preferable that the predetermined time T2, that is, the margin value B is set in consideration of control delay and the like. Although the engine speed of the engine body 11 is in the dangerous speed range A, the combustion state is stable because the operation of the exhaust gas temperature raising device 14 is stopped at this time, and the engine speed is rapidly increased. Ascends and exits the dangerous rotation speed range A at time t24. Further, during the period T1 in which the engine speed is in the dangerous speed range A, the exhaust gas temperature rising process is stopped, but the exhaust gas temperature does not drop early and the exhaust gas denitration process continues. Will be implemented.

Then, at this time t24, when the engine speed passes through the dangerous speed range A, the control device 15 starts the operation of the exhaust gas temperature raising device 14 and opens the extraction gas valve 51. Then, the exhaust gas temperature increasing device 14 starts the exhaust gas temperature increasing process again, and the exhaust gas denitration process is continuously performed. After that, at time t25, the engine speed reaches the target engine speed. Then, at time t26, when the operating area of the vessel goes out of the ECA (regulated area) (OFF), the operation of the SCR denitration device 13 is stopped (OFF) and the operation of the exhaust gas temperature raising device 14 is stopped. The extraction gas valve 51 is closed, and the exhaust gas denitration process ends.

As described above, in the marine diesel engine of the third embodiment, the margin lower limit value of the dangerous speed range A lower than the lower limit value of the dangerous speed range A in which the margin value B is added to the lower limit value of the dangerous speed range A. The control device 15 stops the operation of the exhaust gas temperature raising device 14 (14A) when the current engine speed reaches the margin lower limit value. Therefore, the operation of the exhaust gas temperature raising device 14 can be stopped before the engine speed of the engine body 11 reaches the dangerous engine speed range A, the combustion state of the engine body 11 is stabilized, and the engine speed is appropriately adjusted. It is possible to increase and quickly exit the dangerous rotation speed range A.

[Fourth Embodiment]
FIG. 5 is a time chart showing the operation of the SCR denitration device in the marine diesel engine of the fourth embodiment. The basic configuration of the marine diesel engine of the present embodiment is almost the same as that of the above-described first embodiment, and will be described with reference to FIG. 1 and has the same functions as those of the above-described first embodiment. The members having the same reference numerals are given and detailed description thereof is omitted.

In the marine diesel engine of the fourth embodiment, as shown in FIG. 1, the control device 15 controls the exhaust gas after a predetermined time T3 has elapsed after the current engine speed has passed through the dangerous speed range A. The operation of the temperature raising device 14 (14A) is stopped.

As shown in FIGS. 1 and 5, when the operating area of the ship is within the ECA (regulated area) (ON), the SCR denitration device 13 is operated (ON) and the exhaust gas temperature raising device 14 is operated to extract. The gas valve 51 is opened, and the exhaust gas is subjected to denitration processing. Then, at time t31, the steering wheel 71 is operated, and a command value for increasing the engine speed beyond the dangerous speed range A is output.

When this command value is input at time t31, the control device 15 stops the operation of the exhaust gas temperature raising device 14 and closes the extraction gas valve 51. Further, the control device 15 increases the engine speed by performing control such as increasing the amount of fuel input based on this command value. Then, at time t32, the engine speed enters the dangerous speed range A, but at this time, since the operation of the exhaust gas temperature raising device 14 is stopped, the combustion state of the engine body 11 is stable, The engine speed rapidly increases, and the dangerous speed range A is exited at time t33. Further, during the period T1 in which the engine speed is in the dangerous speed range A, the exhaust gas temperature rising process is stopped, but the exhaust gas temperature does not drop early and the exhaust gas denitration process continues. Will be implemented.

Then, at this time t33, when the engine speed goes out of the dangerous speed range A, the control device 15 causes the exhaust gas temperature raising device at a time t34 when a predetermined time T3 has passed after going out of the dangerous speed range A. 14 is started and the extraction gas valve 51 is opened. Then, the exhaust gas temperature increasing device 14 starts the exhaust gas temperature increasing process again, and the exhaust gas denitration process is continuously performed. Then, at time t35, the engine speed reaches the target engine speed. Then, at time t36, when the operating area of the ship is outside the ECA (regulated area) (OFF), the operation of the SCR denitration device 13 is stopped (OFF) and the operation of the exhaust gas temperature raising device 14 is stopped. The extraction gas valve 51 is closed, and the exhaust gas denitration process ends.

As described above, in the marine diesel engine of the fourth embodiment, the control device 15 controls the exhaust gas temperature raising device 14 after the elapse of the preset predetermined time T2 after the current engine speed has passed the dangerous speed range. Start to operate. Therefore, the exhaust gas temperature raising device 14 is operated after the engine speed completely goes out of the dangerous speed region A, so that the safety of the engine body 11 can be ensured and the exhaust gas denitration by the SCR denitration device 13 can be ensured. The treatment can be carried out appropriately.

10 Marine Diesel Engine 11 Engine Body (Internal Combustion Engine Body)
12 Supercharger 13 SCR denitration device 14 Exhaust gas temperature raising device 15 Control device 21 Cylinder 22 Scavenging trunk 23 Exhaust manifold 31 Compressor
32 turbine 41 SCR reactor 42 reducing agent supply device 51 extraction gas valve 52 extraction valve 61 air cooler G1 air supply line G2, G4 exhaust line G3 intake port G5 extraction gas line G6 extraction line

Claims (8)

Engine body,
A denitration device provided in the exhaust line of the exhaust gas discharged from the engine body,
An exhaust gas temperature raising device for raising the temperature of the exhaust gas flowing into the denitration device,
A control device for controlling the operation of the exhaust gas temperature raising device and for stopping the operation of the exhaust gas temperature raising device when the engine speed is in a preset dangerous speed range.
A marine diesel engine, comprising: The control device stops the operation of the exhaust gas temperature raising device at the time of input of the command value when a command value for increasing the engine speed exceeds the dangerous speed range is input. 1. The marine diesel engine according to 1. The marine diesel engine according to claim 1, wherein the control device stops the operation of the exhaust gas temperature raising device when the current engine speed reaches the dangerous speed range. A margin lower limit value of the dangerous rotation speed region lower than the lower limit value of the dangerous rotation speed region obtained by adding a preset margin value to the lower limit value of the dangerous rotation speed region is set, and the control device sets the current engine rotation speed. The marine diesel engine according to claim 1, wherein the operation of the exhaust gas temperature raising device is stopped when the number reaches the margin lower limit value. The said control apparatus starts operation|movement of the said exhaust gas temperature raising apparatus, when a present engine speed passes the said dangerous speed range, The said Claim 1 characterized by the above-mentioned. Marine diesel engine. The control device starts the operation of the exhaust gas temperature raising device after a lapse of a predetermined time set in advance after the current engine rotational speed has passed through the dangerous rotational speed range. 4. The marine diesel engine according to any one of 4 above. Engine body,
A denitration device provided in the exhaust line of the exhaust gas discharged from the engine body,
An exhaust gas temperature raising device for raising the temperature of the exhaust gas flowing into the denitration device,
In a marine diesel engine equipped with
Controlling the operation of the exhaust gas temperature raising device and stopping the operation of the exhaust gas temperature raising device when the engine speed is in a preset dangerous speed range.
An engine control device characterized by the above. Performing a process of increasing the temperature of the exhaust gas from the engine and performing a denitration process of the exhaust gas when the ship is at least in the air pollutant emission control sea area,
A step of stopping the process of raising the temperature of the exhaust gas when the engine speed enters a preset dangerous speed range,
An engine control method comprising:

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